The present invention relates to paste dispensers and particularly a pump-type dispenser for toothpaste.
There exists a variety of toothpaste dispensing pumps utilizing different operating principals. Once such pump is generally known as a vacuum pump and employs a pair of check valves which operate sequentially to develop a partial vacuum in the space above the paste for drawing the paste upwardly and outwardly through a dispensing nozzle. Another system employs a piston which initially is located at the bottom of a dispensing container and is ratcheted upwardly by a reciprocating plunger to force paste from a nozzle at the top of the dispenser. Other approaches include aerosol-type pressurized dispenser and finally a dispenser in which a hollow dispensing tube with a nozzle at one end is employed and reciprocated through a ratchet mechanism and a piston which moves downwardly to force paste through an open lower end upwardly through the nozzle. U.S. Pat. Nos. 2,732,101 and 4,437,584 are representative of the latter type of dispensers. It has been discovered with the downwardly moving piston forcing paste through the relatively small diameter tube, a significant amount of pressure is required on the actuating lever used for reciprocating the tube in order to force the viscous paste upwardly and through the dispensing nozzle. Thus, with these types of pumps, typically the dispensing operation can be somewhat difficult and the parts prone to failure.